510 research outputs found
A global radiosonde and tracked balloon archive on 16 pressure levels (GRASP) back to 1905 – Part 1: Merging and interpolation to 00:00 and 12:00 GMT
Many observed time series of the global
radiosonde or PILOT networks exist as fragments distributed over different
archives. Identifying and merging these fragments can enhance their value for
studies on the three-dimensional spatial structure of climate change.
<br><br>
The Comprehensive Historical Upper-Air Network (CHUAN version 1.7), which was substantially extended in 2013,
and the Integrated Global Radiosonde
Archive (IGRA) are the most important collections of upper-air measurements
taken before 1958. CHUAN (tracked) balloon data start in 1900, with higher
numbers from the late 1920s onward, whereas IGRA data start in 1937. However,
a substantial fraction of those measurements have not been taken at synoptic
times (preferably 00:00 or 12:00 GMT) and on altitude levels instead of standard
pressure levels. To make them comparable with more recent data, the records
have been brought to synoptic times and standard pressure levels using
state-of-the-art interpolation techniques, employing geopotential information from the
National Oceanic and Atmospheric Administration (NOAA) 20th Century
Reanalysis (NOAA 20CR). From 1958 onward the European Re-Analysis archives
(ERA-40 and ERA-Interim) available at the European Centre for Medium-Range
Weather Forecasts (ECMWF) are the main data sources. These are easier to use,
but pilot data still have to be interpolated to standard pressure levels.
Fractions of the same records distributed over different archives have been
merged, if necessary, taking care that the data remain traceable back to
their original sources. If possible, station IDs assigned by the World
Meteorological Organization (WMO) have been allocated to the station records.
For some records which have never been identified by a WMO ID, a local ID
above 100 000 has been assigned. The merged data set contains 37 wind records
longer than 70 years and 139 temperature records longer than 60 years. It can
be seen as a useful basis for further data processing steps, most notably
homogenization and gridding, after which it should be a valuable resource for
climatological studies.
Homogeneity adjustments for wind using the NOAA-20CR as a reference are
described in Ramella Pralungo and
Haimberger (2014). Reliable homogeneity adjustments for
temperature beyond 1958 using a surface-data-only reanalysis such as
NOAA-20CR as a reference have yet to be created.
All the archives and metadata files are available in ASCII and netCDF format
in the <i>PANGAEA</i> archive <a href="http://dx.doi.org/10.1594/PANGAEA.823617">doi:10.1594/PANGAEA.823617</a>
Quantum Rotor Engines
This chapter presents autonomous quantum engines that generate work in the
form of directed motion for a rotor. We first formulate a prototypical
clock-driven model in a time-dependent framework and demonstrate how it can be
translated into an autonomous engine with the introduction of a planar rotor
degree of freedom. The rotor plays both the roles of internal engine clock and
of work repository. Using the example of a single-qubit piston engine, the
thermodynamic performance is then reviewed. We evaluate the extractable work in
terms of ergotropy, the kinetic energy associated to net directed rotation, as
well as the intrinsic work based on the exerted torque under autonomous
operation; and we compare them with the actual energy output to an external
dissipative load. The chapter closes with a quantum-classical comparison of the
engine's dynamics. For the single-qubit piston example, we propose two
alternative representations of the qubit in an entirely classical framework:
(i) a coin flip model and (ii) a classical magnet moment, showing subtle
differences between the quantum and classical descriptions.Comment: Chapter of the upcoming book "Thermodynamics in the Quantum Regime -
Recent Progress and Outlook
AVENUE21. Connected and Automated Driving: Prospects for Urban Europe
This open access publication examines the impact of connected and automated vehicles on the European city and the conditions that can enable this technology to make a positive contribution to urban development. The authors argue for two theses that have thus far received little attention in scientific discourse: as connected and automated vehicles will not be ready for use in all parts of the city for a long time, previously assumed effects – from traffic safety to traffic performance as well as spatial effects – will need to be re-evaluated. To ensure this technology has a positive impact on the mobility of the future, transport and settlement policy regulations must be adapted and further developed. Established territorial, institutional and organizational boundaries must be investigated and challenged quickly. Despite – or, indeed, because of – the many uncertainties, we find ourselves at the beginning of a new design phase, not only in terms of technology development, but also regarding politics, urban planning, administration and civil society
Description of the ERA-CLIM historical upper-air data
Historical, i.e. pre-1957, upper-air data are a valuable source of
information on the state of the atmosphere, in some parts of the world dating back
to the early 20th century. However, to date, reanalyses have only
partially made use of these data, and only of observations made after 1948.
Even for the period between 1948 (the starting year of the NCEP/NCAR (National Centers for Environmental
Prediction/National Center for Atmospheric Research) reanalysis) and the International Geophysical Year in 1957 (the starting
year of the ERA-40 reanalysis), when the global upper-air coverage reached
more or less its current status, many observations have not yet been digitised. The Comprehensive Historical Upper-Air Network (CHUAN) already
compiled a large collection of pre-1957 upper-air data. In the framework of
the European project ERA-CLIM (European Reanalysis of Global Climate Observations), significant amounts of additional upper-air
data have been catalogued (> 1.3 million station days), imaged
(> 200 000 images) and digitised (> 700 000 station
days) in order to prepare a new input data set for upcoming reanalyses. The
records cover large parts of the globe, focussing on, so far, less well
covered regions such as the tropics, the polar regions and the oceans, and
on very early upper-air data from Europe and the US. The total number of
digitised/inventoried records is 61/101 for moving upper-air data, i.e. data
from ships, etc., and 735/1783 for fixed upper-air stations. Here, we give a
detailed description of the resulting data set including the metadata and the
quality checking procedures applied. The data will be included in the next
version of CHUAN. The data are available at <a href="http://dx.doi.org/10.1594/PANGAEA.821222"target="_blank">doi:10.1594/PANGAEA.821222</a>
Gyroless Spin-Stabilization Controller and Deorbiting Algorithm for CubeSats
CubeSats are becoming increasingly popular in the scientific community. While they provide a whole new range of opportunities for space exploration, they also come with their own challenges. One of the main concerns is the negative impact which they can have in the space debris problem. Commonly lacking from attitude determination and propulsion capabilities, it has been difficult to provide CubeSats with means for active deorbiting. While electric propulsion technology has been emerging for its application in CubeSats, little or no literature is available on methods to enable it to be used for deorbiting purposes, especially within the tight constraints faced by these nanosatellites. We present a new and simple algorithm for CubeSat deorbiting, which proposes the use of novel electric propulsion technology with minimum sensing and actuation capabilities. The algorithm is divided into two stages: a spin-stabilization control; and a deorbiting-phase detection. The spin-stabilization control is inspired by the B-dot controller. It does not require gyroscopes, but only requires magnetometers and magnetorquers as sensors and actuators, respectively. The deorbiting-phase detection is activated once the satellite is spin-stabilized. The algorithm can be easily implementable as it does not require any attitude information other than the orbital information, e.g., from the Global Positioning System receiver, which could be easily installed in CubeSats. The effectiveness of each part of the algorithms is validated through numerical simulations. The proposed algorithms outperform the existing approaches such as deorbiting sails, inflatable structures, and electrodynamic tethers in terms of deorbiting times. Stability and robustness analysis are also provided. The proposed algorithm is ready to be implemented with minimal effort and provides a robust solution to the space junk mitigation efforts
Development of an antimicrobial urinary catheter to inhibit urinary catheter encrustation.
Background: Encrustation of urinary catheters is a frequent problem in patients with long-term indwelling catheters colonised with urease-positive bacteria such as Proteus mirabilis. Catheter blockage may follow catheter encrustation, potentially leading to systemic infection. Prevention of encrustation is difficult and avoidance of recurrence often unsuccessful. One possible preventative strategy is to use a catheter with an antimicrobial surface and development and assessment of such a surface was the aim of this research.
Methods: Initial experiments assessed the antimicrobial activity of silicone impregnated with plant-derived antimicrobials and triclosan using agar diffusion. The longevity of activity of each antimicrobial silicone was examined over a period of 11 weeks following soaking individual pieces of antimicrobial silicone in an artificial urine solution before using agar diffusion to test remaining antimicrobial activity. Live/Dead staining of bacteria colonising the surface of each antimicrobial silicone was employed to determine the bactericidal properties of each antimicrobial silicone. Selected antimicrobial silicones were subsequently evaluated for their ability to prevent catheter encrustation in an in vitro bladder model.
Results: Results showed that antimicrobial activity was obtained using 1% triclosan-impregnated silicone and that this antimicrobial activity was long-lasting (up to 11 weeks). Use of a dip coat silicone formulation, containing 0.2% triclosan, proved effective at delaying catheter encrustation with P. mirabilis metabolites in vitro. In 8 out of 13 independent experiments using dip-coated catheters, no catheter blockage occurred over 7 days, whilst all control catheters blocked during this period. Only on one occasion was delayed encrustation not evident with the treated catheters.
Conclusions: In summary, a dip-coat silicone containing triclosan proved effective in preventing in vitro catheter encrustation caused by P. mirabilis infection. Further studies with triclosan silicone dip coat formulation are warranted, including those that investigate potential host cell toxicity and long-term benefits following its application to indwelling urinary catheters in clinical settings
Decoupling of Deforestation and Soy Production in the Southern Amazon During the Late 2000s
From 2006-2010 deforestation in the Amazon frontier state of Mato Grosso decreased to 30% of its historical average (1996-2005) while agricultural production reached an all time high, achieving the oft-cited objective of increasing production while maintaining forest cover. This study combines satellite data with government deforestation and production statistics to assess land-use transitions and potential market and policy drivers associated with these trends. In the forested region of the state, increased soy production from 2001-2005 was entirely due to cropland expansion into previously cleared areas (74%) or forests (26%). From 2006-2010, 78% of production increases were due to expansion (22% to yield increases), with 91% on previously cleared land. Cropland expansion fell from 10% to 2% of deforestation between the two periods, with pasture expansion accounting for most remaining deforestation. Declining deforestation coincided with a collapse of commodity markets and implementation of policy measures to reduce deforestation. Soybean profitability has since increased to pre-2006 levels while deforestation continued to decline, suggesting that anti-deforestation measures may have influenced the agricultural sector. We found little evidence of leakage of soy expansion into cerrado in Mato Grosso or forests in neighboring Amazon states during the late 2000s, although leakage to more distant regions is possible. This study provides empirical evidence that reduced deforestation and increased agricultural production can occur simultaneously in tropical forest frontiers through productive use of already cleared lands. It remains uncertain whether government and industry-led policies can contain deforestation when market conditions again favor a boom in agricultural expansion
Significant ophthalmoarthropathy associated with ectodermal dysplasia in a child with Marshall-Stickler overlap: a case report
© 2008 Al Kaissi et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Recruitment strategies and rates of a multi-site behavioral intervention for adolescents and young adults with cancer
INTRODUCTION:
To provide an overview of factors related to recruitment of adolescents and young adults (AYA) into research and recruitment rates and reasons for refusal from a multicenter study entitled "Stories and Music for Adolescent/Young Adult Resilience during Transplant" (SMART).
METHODS:
A randomized clinical trial study design was used. The settings included 9 hospitals. The sample included AYAs (aged 11-24 years) who were undergoing a stem cell transplant. Several instruments were used to measure symptom distress, coping, resilience, and quality of life in AYA with cancer.
RESULTS:
A total of 113 AYA were recruited (50%) for this study. Strategies were refined as the study continued to address challenges related to recruitment. We provide a description of recruitment strategies and an evaluation of our planning, implementing, and monitoring of recruitment rates for the SMART study.
DISCUSSION:
When designing a study, careful consideration must be given to factors influencing recruitment as well as special considerations for unique populations. Dissemination of strategies specific to unique populations will be helpful to the design of future research studies
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